Hiding button using permissions


In the Assessment Plan, there is Assessment Result button at the upper left side corner of the Assessment Plan as shown in the below image.
How I can hide it for certain user and show it for certain user using permission?
If it is like other elements in the document, I can do this using permission level (by giving it higher level value).

Below is the code that is responsible for showing this button:

    refresh: function(frm) {
            if (frm.doc.docstatus == 1) {
                    frm.add_custom_button(__("Assessment Result"), function() {
                            frappe.route_options = {
                                    assessment_plan: frm.doc.name,
                                    student_group: frm.doc.student_group
                            frappe.set_route("Form", "Assessment Result Tool");

You can check frappe.user.has_role(“the role to see button”) before frm.add_button() in js. Level based permission is applied to fields I guess.